Hiroshima was 15 kt, 4.23 Mt is 282x that. Fortunately this thing is small enough that it would burst at high altitude and only do minor damage on the ground:
It's about 10 times larger than the meteor that fell over Russia a few years back (the Chelyabinsk meteor [1]), so not too big in the grand scheme of things. It would not really have any major effects unless it hit near a populated area, which is very unlikely. If it did impact the Earth it would probably hit the Pacific ocean.
The biggest surprise (for me) from the dart mission was that the asteroid wasn't one big rock. It's more like, dust and gravel and boulders all stuck together with gravity.
As much as I love a certain Michael Bay movie about a rag-tag group of drillers tasked with drilling an asteroid in space, it seems unlikely that would be necessary.
Seems like, the two obvious approaches are a push or an explosion.
Using an explosion to diffuse the parts of an asteroid, and that might be a whole lot easier than previously thought, since the thing is only weakly held together. The other approach of giving it a push seem a whole lot tougher, since they're not rigid.
> A gravity tractor is a theoretical spacecraft that would deflect another object in space, typically a potentially hazardous asteroid that might impact Earth, without physically contacting it, using only its gravitational field to transmit the required impulse.[1][2] The gravitational force of a nearby space vehicle, though small, is able to alter the path of a much larger asteroid if the vehicle spends enough time close to it; all that is required is that the vehicle thrust in a consistent direction relative to the asteroid's path, and that neither the vehicle nor its expelled reaction mass come in direct contact with the asteroid.
New object, current 1-in-625 chance of impact, impact could cause local death and damage, more observational data will refine the trajectory estimations.
I can't really tell how news-like this is. Mostly, my question would be: this object is called 2023 DW, does it mean we went 2023 AA, AB, ..., DA, DB, ... DW? If so it's interesting that only ~100 new asteroids are observed and labeled so far this year. Maybe the categorization is somehow different than I understand.
"2023 DW" is a provisional minor-planet designation [0]. The "D" indicates that it was discovered in the second half of February (Feb. 16-28), and the "W" indicates that it was the 22nd minor planet discovered in that time frame.
The last time an asteroid reached a 1 on the Torino scale was late January. That asteroid is 2023 AJ1. It was downgraded to 0 on the scale in early February, after further observations decreased the estimated chance it will hit the earth.
Overall, objects reach a 1 on the Torino scale 3-4 times a year. No objects have reached level 2 or above since 2006.
- "Due to exaggerated press coverage of Level 1 asteroids, a rewording of the Torino Scale was published in 2005, adding more details and renaming the categories: in particular, Level 1 was changed from "Events meriting careful monitoring" to "Normal".
With space things we typically deal with astronomical odds, so I'd say 1:600 is a solid "may" and on the internet looks like 'probably not' to most readers.
Jokes aside, could anyone knowledgeable explain why this comes down to a probability. Isn't the speed and direction of objects traveling in space constant and predictable? What are the unknown variables?
The speed and direction of objects moving through space is deterministic, but it is neither constant (obviously) nor completely predictable except in very special cases. In general the motion of systems of three or more bodies are chaotic, i.e. very small changes in initial conditions can result in very large changes in position and velocity in the future. Also, we can't measure positions and velocities with infinite precision. This has nothing to do with quantum mechanics, it's just that the data that comes out of our instruments has finite precision and so there will always be measurement errors. Finally, earth is a very small target, so figuring out whether something will hit it requires a lot of precision.
Also, quoting from the original article: "Often when new objects are first discovered, it takes several weeks of data to reduce the uncertainties and adequately predict their orbits years into the future."
Yes, but only with sufficient observation. Since this body was recently discovered, there likely hasn't been enough observation time to know the direction and velocity of the object with great certainty. The more we observe it, the better we'll know where it'll be in 20 years.
For any two objects in orbits around a common body (like the sun) to match their orbits, they need to have their locations match and their velocity, at the same time. To collide, you only need your location to match.
One way to do this is to get to a matching location and then do a hard change of velocity so that the asteroid is now in a stable orbit. But that's a lot of energy for a rock with a mess measured using scientific notation.
There are better candidates out there where we could make a tiny change to their orbit and have them be captured naturally due to relative velocities being much closer to matching. Still a lot of energy, but a lot less.
From a purely technical perspective: maybe. We'd need to know how similar the object's orbit is relative to Earth's. If the orbit is roughly coplanar and concentric with Earth, it will cost less change in velocity (delta-V) to reduce the differences and bring it into a stable orbit. The more different it is (e.g. if it swings all the up to Jupiter and back), the more it will cost.
Once you know how much dV is required to capture, we'd next need to put that much dV at the object, which would be even more costly to launch.
Lastly, depending on the object's composition it may not be possible to even apply much dV to it. If it's a essentially a coalesced pile of rubble, any force applied will just break it into pieces. If it's roughly solid, then maybe.
Fun fact: Earth has had more than one "moon" in the past, they just tend to not last long before they're kicked out of orbit. [0]
Even if we break it up and capture a chunk it would be both a huge wealth of knowledge and if the chunks was big enough it could be extremely useful construct material
If we do that with rocket power, and not some complicated gravity-assist path, then we can look at New Horizons. That used an Atlas V rocket at around 570 tons to get the 478 kg payload up to 16 km/s. That's a 1:1000 mass ratio.
Once you've caught up, you've got to turn things around and slow down. But you're talking about another 1:1000 or more mass ratio, leaving you with a few grams of material.
This is all hand-waving to give a rough idea of the problem.
We've had a few asteroid sample-return mission. Hayabusa2 returned a few grams of material from 162173 Ryugu. The hope is that OSIRIS-REx will return 60 grams from 101955 Bennu this fall. These used ion thrusters (more efficient than chemical rockets) and atmospheric braking to help slow down.
Still, none of this is anywhere near being useful as construction material. It would be far cheaper to bring it up from Earth.
I was thinking gravity and atmospheric assists to get delta v required. You have to do something complex to pull this off. Or blow off a small piece to deflect the main bit and capture a small artifact
You can check the latest probabilities here: https://cneos.jpl.nasa.gov/sentry/details.html#?des=2023%20D...